Asteraceae (tribe Heliantheae) subtribe Chaenactidinae(synonym of Asteraceae tribe Heliantheae subtribe Chaenactidinae) |
Venegasia |
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canyon-sunflower, venegasia |
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Habit | Annuals, biennials, perennials, subshrubs, shrubs, or treelets, 1–80(–300) cm (some rhizomatous or with woody caudices). | Subshrubs or shrubs, 50–150(–250+) cm. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | erect. |
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Leaves | basal, basal and cauline, or cauline; opposite or alternate; usually petiolate, sometimes sessile; blades mostly cordate, deltate, elliptic, lanceolate, linear, oblanceolate, oblong, obovate, ovate, rhombic, or spatulate, often 1–2-pinnately or -ternately lobed (lobes mostly filiform to linear, lanceolate, or oblanceolate), ultimate margins entire or toothed, faces ± lanate to woolly, or hispidulous to scabrellous or strigose, sometimes glabrescent, sometimes stipitate-glandular, rarely glabrous, often gland-dotted. |
cauline; opposite (proximal) or alternate (most); petiolate; blades (3-nerved) rounded-deltate or cordate to ovate, margins toothed or subentire, faces: abaxial puberulent and/or gland-dotted. |
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Involucres | campanulate to narrowly cylindric or obconic, or hemispheric to rotate. |
hemispheric to globose, 12–25+ mm diam. |
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Receptacles | conic, flat, or hemispheric, often knobby or pitted (sometimes hairy or gland-dotted), usually epaleate (paleae sometimes subulate scales in Chaenactis; in Bartlettia, linear, membranous, hairy scales, each appressed to and shed with an associated cypsela may be interpreted as paleae). |
flat or convex, pitted (pubescent), epaleate. |
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Ray florets | 0 (corollas of peripheral florets sometimes notably larger than those of the inner, then zygomorphic, showy, and somewhat raylike, e.g., Chaenactis spp.) or (1–)4–21(–60+), pistillate, fertile; corollas yellow, orange, red, purplish, or whitish (persistent, marcescent in Arnica dealbata). |
12–34, pistillate, fertile; corollas yellow. |
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Disc florets | 4–200+, usually bisexual, fertile (functionally staminate in Arnica dealbata); corollas yellow, orange, purplish, or whitish, usually hairy and/or gland-dotted or stipitate-glandular, tubes shorter than to longer than cylindric or campanulate to funnelform throats, lobes 5, deltate to linear; anther thecae pale; stigmatic papillae in 2 lines. |
35–150+; bisexual, fertile; corollas yellow, tubes (densely glandular-hairy at bases) shorter than campanulate to narrowly urceolate throats, lobes 5, ovate-deltate. |
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Phyllaries | usually persistent, 4–60+ in 1–4+ series (usually erect at flowering, usually reflexed in fruit, usually distinct, basally coherent in some Arnica spp., mostly lance-ovate, linear, or ovate, unequal to subequal, mostly herbaceous to membranous, outer foliaceous in Venegasia). |
persistent (all or outer), 20–40+ in 3–4+ series (at least outer reflexed in fruit, outer rotund to oblong, herbaceous-foliaceous, inner oblanceolate, membranous or scarious, basally indurate). |
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Calyculi | usually 0 (sometimes 1–3 bractlets in Schkuhria). |
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Heads | usually radiate, sometimes discoid, rarely radiant (Chaenactis spp.), borne singly, or in clusters, or in corymbiform, cymiform, or paniculiform arrays. |
radiate, borne singly or in ± corymbiform arrays. |
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Cypselae | mostly obpyramidal and 4–5-angled, sometimes clavate, columnar, cylindric, or fusiform, sometimes compressed and ± linear (e.g., Chaenactis, Hulsea) or obcompressed (e.g., Arnica dealbata, Bartlettia; lengths usually 3+ times diams.), faces usually hairy and/or gland-dotted; pappi falling, fragile, or persistent, usually of 6–80 distinct or basally connate bristles, or of 4–20 distinct (or basally connate) scales, all, some, or none aristate, sometimes pappi none. |
clavate or fusiform, sometimes arcuate, obscurely 4–5-angled, ca. 20-nerved, glabrous, minutely papillose; pappi 0. |
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x | = 19. |
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Asteraceae (tribe Heliantheae) subtribe Chaenactidinae |
Venegasia |
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Distribution | North America; Mexico; Central America; South America (Bahia) |
CA; nw Mexico |
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Discussion | Genera 25, species 129 (19 genera, 83 species in the flora). The circumscription of Chaenactidinae used here (that of H. Robinson 1981) contrasts sharply with that of B. G. Baldwin (Baldwin and B. L. Wessa 2000; Baldwin et al. 2002). Baldwin included Chaenactis, Dimeresia (here segregated in Dimeresiinae), and Orochaenactis in his Chaenactidinae (as sole subtribe in his Chaenactideae) and placed other genera of Chaenactidinae in the sense of Robinson as follows: Amauriopsis, Bahia, Bartlettia, Chamaechaenactis, Florestina, Hymenothrix, Palafoxia, Peucephyllum, Picradeniopsis, Platyschkuhria, Psathyrotopsis, and Schkuhria in Bahiinae (in Bahieae); Arnica in Arnicinae (in Madieae); Hulsea in Hulseinae (in Madieae); Syntrichopappus in Baeriinae (in Madieae); Venegasia in Venegasiinae (in Madieae); and Jamesianthus in Pectidinae (in Tageteae). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species 1. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 21, p. 364. | FNA vol. 21, p. 385. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | subtribe Bahiinae, subtribe Palafoxiinae | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | Rydberg: in N. L. Britton et al., N. Amer. Fl. 34: 63. (1914) | de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 6: 43. (1838) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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